单选题
Human facial expressions differ from those of animals in the degree to which they can be deliberately controlled and modified.
【正确答案】
C
【答案解析】deliberately和intentionally意思相同：故意，蓄意地。sufficient：足够的，充分的。This is sufficient for my needs. 足够我用了。noticeable：明显的，易见的。There is no noticeable difference. 二者之间没有显著差异。absolutely：绝对地。He's absolutely correct. 他绝对正确。